Benedict will tell you to install an item your ship cannot support if you find one. While it is technically possible to install a dual turbolaser on a ship with a 15 mw reactor it leaves inadequate power for shields, life support, and engines; and I can't find anything in the XML that would prevent him from telling me to install it if I found it while flying a Wolfen with its 10 mw starting reactor where it is completely impossible.

Station loot bypasses the Eridani level 3 limit and the special Benedict encounters can have up to level 5 loot (Anarchist Gatherings and Satellites have a 10% chance of using trMajorItems3, which is level 3 with level curve 2, and a gathering is generated with 2-4 satellites).

Even the Centauri CLAW and heavy CLAW exceed the real capacity of a Wolfen's starting reactor. They also may be impossible to install on mod ships either because of scripted limitations or because it is possible for a mod ship to have only one weapon slot.

Does he also turn up in Tau Ceti? That would would get messy, seeing as he seems to rely on the presence of those little mission giving habitats and I don't think they're guaranteed to turn up in Tau Ceti.

I’ve got a bug to add to this one, myself. If you have a weapon in your hold that Benedict tells you to go get installed, but you sell it instead, going back to the Sisters will still have him telling you to go install it. If the weapon in question was, say, a Bolide blaster or a Centauri recoilless cannon, you can’t just buy it back to install it, so there’s no way to advance beyond that particular quest.